What problem does it solve? Setting up RL post-training pipelines for large language models requires coordinating distributed training, high-throughput inference, and data management across many GPUs, which is complex to build from scratch. ## Core Features & Use Cases - GRPO and PPO Training: Run group-relative policy optimization and other RL algorithms with Megatron-LM parallelism (TP, PP, DP, SP) and SGLang-based rollout generation. - Multi-Turn Agentic Training: Define custom generate functions for tool-calling and multi-step reasoning workflows with proper loss masking. - Async and Colocated Modes: Overlap rollout and training for higher throughput, or share GPUs between training and inference to reduce memory. - Use Case: Train a Qwen3-4B reasoning model on math problems by preparing JSONL prompts with labels, sourcing a pre-configured model script, and launching GRPO training across 8 GPUs. ## Quick Start Use the slime skill to launch GRPO training on my Qwen3-4B model with the math dataset at /data/train.jsonl across 8 GPUs.